A system that recognizes a shape of a traveling road of a vehicle or a traffic rule using road map data and automatically controls traveling of the vehicle is known. In such a system, there is a possibility that when estimation accuracy of a position and posture of a vehicle is deteriorated in road map data, a shape of a traveling road or a traffic rule is erroneously referenced and dangerous travel control is caused. Under such a situation, a state in which automatic driving control by the system can continue is not allowed and thus, switching into manual driving is needed, however, there is a problem that even though a control right is abruptly handed over from the system, a driver is not able to instantly react.
In relation to the problem, a technology disclosed in PTL 1 is known. In PTL 1, a technology in which stability of automatic driving control is determined according to a detection state of a white line in front of an own vehicle and displaying is performed on the on-vehicle display device based on the determination result.